I really am at my wits end

E is 8 months and is a terrible sleeper at night time. days she takes good naps most of the time, but takes 30-45 minutes of crying to get down a lot of the time. She very rarely settles herself, and I really am finding this very difficult now.
Nights are our nemesis. She has never been a good night time sleeper, never sttn, and we rarely get more than a 3 or 4 hour stretch of sleep. Most nights she is up 5 or 6 times, but we have had several nights recently where it has been closer to 20

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She has reflux but is medicated to the max amount that our consultant will go. I think she is uncomfortable as the night wears on (and her meds wear off iyswim), but that doesn't explain all the issues up until that point. Everything just seems to compound everything else - she is OT (she must be after all those nw's), takes ages to settle for bedtime, is still swaddled as weaning has been an absolute nightmare, and just seems to wake for no apparent reason. She will *scream* for 1.5 hours until I feed her sometimes even though she is not very hungry, so she must have some sort of feed to sleep habit but I have no idea how to break it while things are like this

.
I shh/pat for every nap - sometimes takes 45 mins or more of her screaming - and do resort to feeding her sometimes as DS is on his own downstairs on his own. But 75% of the time she will settle without being fed.
NW's I try to shh/pat her - sometimes it works, sometimes not. I usually feed her 2 or 3 times (never less) in the night as she just screams inconsolably for (literally) hours sometimes.
Our daytime EASY looks ok, but is so inconsistent depending on her nights/night feeds etc. Solids are done whenever I can fit them in around BF's, her medication (which has to be given on an empty stomach and 30 mins before food) but she eats 3 meals a day, and has 4 BF's. I do 3 hours A times, and she will generally take 1.25-2 hour naps but sometimes shorter ones and wakes OT in the afternoon.
Today was
wake 7am (but had been up 11 times in the night and I had fed her back to sleep at 5am as I couldn't settle her any other way).
S 10am - 12
S 3.40 (screamed for ages and wouldn't settle til then) - 4.50
Started bedtime BF at 7pm, and she's still up there screaming now (with dh)

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ETA: settled at 8.20pm and now screaming again at 8.45

. I'm starting to feel so angry at her

. ETA: screaming again at 9.25...and still going at 9.50 - agh!
What should I try first? I really cannot see any of this clearly as I'm so exhausted and past all this now. I hate this so much
Thanks anyone for wading through all this. sorry for being such a grouch